<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.DriverManager" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.ResultSet" %><%--
  Created by IntelliJ IDEA.
  User: cc
  Date: 2020/10/2
  Time: 10:46
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    request.setCharacterEncoding("utf-8");
    String username = request.getParameter("username");
    String password = request.getParameter("password");

//建立数据库连接
    Class.forName("com.mysql.jdbc.Driver");

    String url = "jdbc:mysql://localhost:3306/books";
    Connection connection = DriverManager.getConnection(url,"root","root");

    //sql模板
    String sql = "select * from user where username = ? and password = ?";
    //使用PreparedStatement对象执行sql语句
    PreparedStatement ps = connection.prepareStatement(sql);

    ps.setString(1,username);
    ps.setString(2,password);

    ResultSet rs = ps.executeQuery();

    if (rs.next()){
        //表示登录成功
        session.setAttribute("username","username");
        response.sendRedirect("home.jsp");
    }else{
        //表示登录未成功
        out.print("登录失败，3秒之后跳转登陆页面");
        response.setHeader("refresh","3;url=login.jsp");
    }
%>